Garnet vs Ristretto

Garnet is a free remote cache-store from Microsoft Research for self-hosted use on Linux, macOS, and Windows. It uses RESP and works with many unmodified Redis clients, including StackExchange.Redis; documented libraries also include Jedis, Redisson, redis-py, node_redis, and go-redis. Its data APIs cover strings, lists, hashes, sets, sorted sets, geo operations, HyperLogLog, bitmaps, ACLs, pub/sub, transactions, and Lua scripting. Garnet can store datasets larger than memory on local or cloud storage and supports checkpointing and recovery. Multi-node mode provides sharding, state migration, and replication. Developers can register C# data structures and read-modify-write operations through its custom operator framework. TLS/SSL and password-based RESP authentication are supported. DiskANN vector database support and Bf-Tree range indexes are marked preview. Garnet is MIT-licensed, but is not intended as a fully compatible Redis replacement and does not support Redis modules. The self-hosted plan is free; you manage infrastructure, updates, and operations. The managed Azure Cosmos DB Garnet Cache is in expanded Private Preview, with no price listed.

Ristretto is a free, open-source Go library for an in-process cache of key-value data, designed for concurrent use, performance and correctness. It keeps data in memory in a single process rather than operating as a distributed cache. TinyLFU admission and SampledLFU eviction are paired to target high hit ratios; applications define item cost, allowing a valuable large item to displace several smaller ones. The project attributes throughput to contention management, batching and eventual consistency. Goroutines can use the cache concurrently with little throughput degradation, according to the project, and optional metrics cover throughput, hit ratios and other statistics. A Set for a new item may be dropped in the Set buffer or admission policy, while updates are guaranteed. Ristretto requires Go 1.21 or later and Go modules. Version 2 supports generics, which the project recommends for new programs. The repository is licensed under Apache License, Version 2.0, and describes the library as production-ready. Its README names Badger and Dgraph as projects using it.